Data transmission device, reception device, data transmission system, and data transmission method

ABSTRACT

Proper data is selected from a plurality of data which are multiplexed and transmitted to download the proper data. The maker and model of a receiver and the version of a control program are stored in a load section as a maker ID, a model ID, and a version ID. The section number and the total number of sections are also stored. It is checked whether the maker ID and the model ID coincide with those stored in the ROM of the receiver to check whether the version number is newer than that of the control program of the receiver. Therefore, it can be checked whether the program should be downloaded. With reference to the list of section numbers which have been downloaded, it can be found whether a program divided into a plurality of sections to be transmitted is completely downloaded. With reference to the list of section numbers and the total number of sections, the progress state of downloading can be known.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a data transmission device, areception device, a data transmission system, and a data transmissionmethod which are used when a plurality of program data are transmittedby using, e.g., digital satellite broadcast.

[0003] 2. Description of the Related Art

[0004] At present, digital satellite broadcast which transmits digitaldata by using a communication satellite to perform broadcast has spread.In this digital satellite broadcast, video and audio signals arecompressed and encoded by a predetermined scheme, and the compressed andencoded video and audio signals are transmitted to viewers through thecommunication satellite. As a compressing/coding scheme for video andaudio signals, for example, MPEG2 (Moving Picture Experts Group) isused.

[0005]FIG. 10 shows the outline of a typical digital broadcast system.The program transmission side is constituted by an up-link station, aprogram provider, and a management system.

[0006] Video/audio data from a program provider 101 is supplied to anencoder, multiplexer 103 of MPEG (Moving Pictures Expert Group) 2 of anup-link station 102. The video/audio data is compressed in the MPEG2encoder, multiplexer 103, and the compressed video/audio data is filledin a packet having a length of 188 bytes. A plurality of programs andpackets of video/audio data corresponding to the programs aremultiplexed to form a transport packet of MPEG2. A large number oftransport packets are connected to each other to form a transportstream. The number of transport streams corresponds to the number oftransponders mounted on a communication satellite.

[0007] The MPEG2 transport packets are supplied to a transmission system104. In the transmission system 104, processes such as a scrambleprocess for each packet, error correction coding for each packet, andmodulation are performed, and a modulated output is supplied to atransmission antenna 105. The scramble process is required to realizeconditional access used to control the audiovisual quality for eachviewer. For example, a pay-per view contract in which only a certainprogram is watched every paying is made possible. A key for cancelingthe scramble is supplied from a key management system 106 to the MPEG2encoder, multiplexer 103, and is inserted into the transport packet asone of packets like video/audio information.

[0008] The MPEG2 packets are integrally managed by a program managementsystem 107. The program management system 107 is coupled to the keymanagement system 106 to decode a key for canceling scramble. A clientmanagement system 108 is arranged to manage items or the like related toaudiovisual contracts. Accounting information is transmitted between theclient management system 108 and the house of a viewer through atelephone line 109.

[0009] Broadcast radio wave is transmitted from the transmission antenna105 and received by a reception antenna 111 of each house through acommunication satellite 110. A receiver 112 is connected to thereception antenna 111. The receiver 112 is constituted by a tuner fordesignating a reception transponder, a demodulator, a scramble unit forcanceling scramble, a demultiplexer for designating separate packets, avideo decoder, an audio decoder, and the like. Decoded video/audiosignals are supplied to a television receiver 113.

[0010] A key for canceling scramble is encoded and transmitted asrelevant information together with image/voice. The key for solvingcryptography is stored in an IC card 114 inserted in the receiver 112.Program scrambles which can be solved by a transmission side can becontrolled by the transmission side on the basis of the contractinformation of each reception system. A receiver having a conditionalaccess function is called an IRD (Integrated Receiver/Decoder).

[0011] The above digital satellite broadcast system has only just begunto be practically used, and a program for controlling a recent receiveron a reception side may be variably changed. For this reason, thisprogram is stored as data in a programmable ROM built in the receiver.As the programmable ROM, a flash ROM such as an EEPROM (ElectricallyErasable Programmable ROM) is known. This change generally has an objectto provide new services and additional values to clients. Severalmethods can be effective as countermeasures against the change inprogram.

[0012] For example, when a program ROM built in a receiver is replacedwith another one, or the receiver is entirely replaced with another one,a countermeasure against the change in program can be made. When an ICcard in which a new program is stored is distributed to a client byusing the interface, for an IC card, arranged in the receiver, the newprogram can be loaded from the IC card. However, when a large number ofreceivers which have been arranged, it is difficult to replace the ROMsof the receivers and collect the receivers. In addition, a method ofdistributing IC cards requires high cost. Since each IC card has arelatively small memory capacity, the IC card cannot easily store aprogram.

[0013] As a method of solving the above problem, the following method isprovided. That is, latest program information is received from atransmission side, and this program is loaded on a receiver on areception side. More specifically, program data is inserted into a datastream transmitted by satellite broadcast using, e.g., the MPEG2 system,and the program data is received by a viewer by means of a receiver todownload the program data. The downloaded program data is temporarilywritten in, e.g., a RAM built in the receiver, and the program data istransferred from the RAM to a flash ROM, thereby updating the program.

[0014] A piece of software of one type is conventionally applied to allreception devices. More specifically, a necessary piece of softwarecannot be selected from pieces of software of various types. For thisreason, on the receiver side, the type of a host processor (CPU) or anOS (Operation System), the type of an interpreter for executing aprogram, or the like must be limited to one. Therefore, program datacannot be downloaded on a receiver in which these types are notintegrated.

[0015] For example, in a personal computer or the like, when a programis to be downloaded, an operator examines the version of the program,and the version can be compared with the version of the same programowned by the operator at present. In this manner, in a personal computeror the like, the programs whose versions are equal to each other can beprevented from being repetitively downloaded.

[0016] However, downloading by such a conventional receiver forsatellite broadcast is performed regardless of the version of a programto be downloaded. Therefore, it is a problem that a program whoseversion is equal to the version of the program which has been downloadedmay be repetitively downloaded in vain. It is another problem that theversion of the downloaded program may be older than the version of theprogram which is owned.

[0017] Also in downloading by a personal computer, determination ofversion information is left to an operator's hand. For this reason, thefailure described above may occur in the downloading.

[0018] In addition, program data to be downloaded has a size of, e.g.,several MBytes. Therefore, the downloading of the program data requiresseveral minutes or several ten minutes. In a conventional system, aprogress state of downloading, e.g., the rate of the size of downloadeddata to the total size of program data is not displayed. For thisreason, the following problem arises. That is, time of the end ofdownloading cannot be recognized, and an operator who executes thedownloading is displeasured.

[0019] On the other hand, when a different types of program data are tobe transmitted, the following method may be used. That is, a pluralityof transmission paths are used, and these program data are transmittedthrough different paths, respectively. For example, in this satellitebroadcast, a plurality of transponders to which different carrierfrequencies are allocated are used, so that data streams are transmittedto receivers. Therefore, transponders can be allocated to receiversdepending on the makers and models of the receivers. However, aconventional system has no information representing a transponder fromwhich specific program data is transmitted. For this reason,corresponding program data cannot be substantially downloaded on thereception side.

SUMMARY OF THE INVENTION

[0020] Therefore, it is an object of the present invention to provide adata transmission device, a reception device, a data transmissionsystem, and a-data transmission method which can select proper data froma plurality of data which are multiplexed and transmitted to downloadthe selected proper data.

[0021] In order to solve the above problem, the present inventionprovides a data transmission device for time-divisionally multiplexingsignals of a plurality of channels and further multiplexing theplurality of time-divisionally multiplexed signals to simultaneouslytransmit the signals, characterized in that receiver makeridentification information for identifying makers of reception devicesfor receiving transmitted information and receiver model identificationinformation for identifying models of the makers of the receptiondevices are transmitted.

[0022] In order to solve the above problem, the present inventionprovides a data reception device for designating a predetermined signalfrom multiplexed and transmitted signals to receive the predeterminedsignal, characterized by comprising: means for extracting only necessaryinformation on the basis of receiver maker identification informationand receiver model identification information included in the receivedsignal to store the extracted information; and control means for usingthe stored information as a program for unit control.

[0023] In order to solve the above problem, the present inventionprovides a data transmission system for time-divisionally multiplexingsignals of a plurality of channels and further multiplexing theplurality of time-divisionally multiplexed signals to simultaneouslytransmit the signals, and designating a predetermined signal from themultiplexed and transmitted signals to receive the predetermined signal,characterized by comprising: transmission means for transmittingreceiver maker identification information for identifying makers ofreception devices for receiving transmitted information and receivermodel identification information for identifying models of the makers ofthe reception devices; reception means for receiving the transmittedinformation; means for extracting only necessary information on thebasis of the receiver maker identification information and the receivermodel identification information included in the received information tostore the extracted information; and control means for using the storedinformation as a program for unit control.

[0024] In order to solve the above problem, the present inventionprovides a data transmission method for time-divisionally multiplexingsignals of a plurality of channels and further multiplexing theplurality of time-divisionally multiplexed signals to simultaneouslytransmit the signals, characterized in that receiver makeridentification information for identifying makers of reception devicesfor receiving transmitted information and receiver model identificationinformation for identifying models of the makers of the receptiondevices are transmitted.

[0025] As described above, according to the present invention, sincereceiver maker identification information for identifying makers ofreception devices for receiving transmitted information and receivermodel identification information for identifying models of the makers ofthe reception devices are transmitted, proper information can beselected from pieces of multiplexed and transmitted information toreceive the proper information.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a block diagram showing an example of a datatransmission system which can be applied to the embodiment.

[0027]FIG. 2 is a schematic diagram for explaining a transport packet.

[0028]FIG. 3 is a block diagram showing an example of the more detailedarrangement of a receiver.

[0029]FIG. 4 is a schematic diagram showing an example of thearrangement of a load section.

[0030]FIG. 5 is a schematic diagram showing an example of thearrangement of a load control section.

[0031]FIG. 6 is a flow chart showing processes performed when atransponder from which a load section corresponding to a receiver istransmitted is designated.

[0032]FIG. 7 is a schematic diagram for explaining the correspondencebetween transponders and the receiver maker identification numbers andmodel identification numbers of program data transmitted from thecorresponding transponders.

[0033]FIG. 8 is a flow chart used when a radio wave from a designatedtransponder is received to download a program.

[0034]FIG. 9 is a schematic diagram showing an example of the display ofa progress state of downloading.

[0035]FIG. 10 is a view showing the outline of a typical digitalbroadcast system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0036] An embodiment of the present invention will be described belowwith reference to the drawings. FIG. 1 shows an example of a datatransmission system which can be applied to one embodiment of thepresent invention. In this system, video data, audio data, other datawhich are converted into a serial data stream on a transmission side aremodulated, and the data stream is converted into a radio wave in apredetermined frequency band by a transmission equipment 4 to betransmitted. This radio wave is repeated by a communication satellite 5and received by a receiver 6.

[0037] On the transmission side, a video signal and an audio signal aresupplied to an encoder 1. In the encoder 1, the supplied signals arehigh-efficiently encoded to be encoded.

[0038] In this embodiment, an MPEG2 system is used for high efficiencyencoding in the encoder 1. More specifically, the video signal issubjected to motion compensation by DCT (Discrete Cosine Transformation)and motion vector calculation, and the video signal is quantized to beencoded. The audio signal is subjected to sub-band encoding by usingaudiovisual psychological encoding.

[0039] In the encoder 1, the encoded video signal and the encoded audiosignal are time-divisionally multiplexed to form a serial data stream.The data stream is supplied to a multiplexer 2. In this system, to copewith transmission through a plurality of channels in one frequency band,a plurality of encoders 1, e.g., of 6 channels, can be set in eachfrequency band. Data streams output from the respective encoders 1 aresupplied to the multiplexer 2.

[0040] In the multiplexer 2, the video/audio signals, program code data,and the additional data which are supplied from the plurality ofencoders 1 are further multiplexed by time-divisional multiplexing. Theadditional data includes, e.g., text data or the like. In the MPEG2, thedata streams are divided in units called packets to be transmitted. Asshown in FIG. 2, one packet is constituted by a 4-byte header portionand a 184-byte pay-load portion, and has a size of 188 bytes. Thedivided data streams are stored in the pay-load portion. In the headerportion, information of packets and information representing therelationship between the packets are stored. A PID serving asidentification information of the packets is added to the headerportion.

[0041] More specifically, in this multiplexer 2, the data stream isdivided every 184 bytes, and predetermined header information is addedto the data to generate a packet, thereby multiplexing the data stream.As a result, the same PID is added to transport packets generated bydata streams output from the same encoder. A stream obtained byconnecting transport packets described above to each other by atransmission form is called a transport stream. The transport streamoutput from the multiplexer 2 is supplied to a modulator 3.

[0042] In the modulator 3, QPSK (Quadrature Phase Shift Keying)modulation is performed to a transport packet to obtain a modulatedsignal in a predetermined frequency band, and the modulated signal isoutput. The modulated signal output from the modulator 3 is supplied tothe transmission equipment 4 having a power amplifier and a transmissionantenna.

[0043] Actually, a scramble process for a transport packet, an errorcorrection coding process by a Read-Solomon code, an interleavingprocess to cope with a burst error, a convolution coding process, andthe like are performed.

[0044] Transmission can be performed with respect to a plurality offrequency bands. For this reason, in this system, as shown in FIG. 1, aplurality of arrangements each constituted by the plurality of encoders1, the multiplexer 2, and the modulator 3 can be arranged. Therespective modulators 3 perform modulation in frequency bands which aredifferent from each other. Modulated signals output from the modulators3 are supplied to the transmission equipment 4.

[0045] The modulated signals are converted into radio waves, and theradio waves are transmitted from the transmission equipment 4 to thecommunication satellite 5. The communication satellite 5 comprisestransponders (satellite repeaters). The transponder repeats a radio wavein a predetermined frequency band. When a plurality of transpondershaving frequency bands corresponding to the transponders are arranged onthe communication satellite 5, radio waves in a plurality of frequencybands can be simultaneously repeated. For example, 28 transponders arearranged on the communication satellite 5. Therefore, in transmissionfrom the transmission equipment 4 to the communication satellite 5,radio waves in a plurality of frequency bands corresponding to thenumber of transponders arranged on the communication satellite 5 aresimultaneously transmitted.

[0046] In many cases, the plurality of transponders are managed bydifferent entrepreneurs, respectively.

[0047] A radio wave transmitted from the transmission equipment 4 andrepeated by the communication satellite 5 is received by an antenna 7 ofthe receiver 6 to be a reception signal. The reception signal issupplied to a tuner 8 and subjected to predetermined signal processing(to be described later) by a demodulator 9, an error correcting unit 10,a separation unit 11, an MPEG decoder 12, and the like to output videoand audio signals, and predetermined data can be obtained.

[0048]FIG. 3 shows an example of a more detailed arrangement of thereceiver 6. The reception signal received by the antenna 7 is suppliedto the tuner 8. The tuner 8 designates a transponder from which a signalis received by the tuner 8 to select a predetermined frequency band.The-selected reception signal is supplied to the demodulator 9 to besubjected to a QPSK demodulation process, and a transport packet whoseerror is corrected by the error correcting unit 10 is recovered. Theerror correcting unit 10 decodes a Read-Solomon code and performs aViterbi decoding process to perform error correction. This transportpacket is supplied to the separation unit (demultiplexer) 11.

[0049] In the separation unit 11, a packet of a desired channel isseparated from other packets, and descramble for the packet isperformed. The packet is further separated into video data, audio data,and additional data (including program information) on the basis ofinformation of a header portion. The video data is decoded by a videodecoder 12V to obtain a received video signal. The audio data is decodedby an audio decoder 12A to obtain a received audio signal. These videodecoder 12V and the audio decoder 12A are included in the MPEG decoder12 (see FIG. 1). The additional data is supplied to a unit controller20. An adder 25 adds a display signal to the decoded video data, and anoutput video signal from the adder 25 is displayed on a display.Similarly, the decoded audio signal is amplified by, e.g., an amplifier,to be output from a loudspeaker.

[0050] The unit controller 20 is to control the operation of the entirereceiver, and is constituted by a microcomputer. A ROM 21, a flashmemory 22, a RAM 23, and a screen display generator 24 are coupled tothe unit controller 20. In the ROM 21, a program for download control isstored. The download control performed by the unit controller 20 is madeon the basis of the program stored in the ROM 21. A program for generaloperation control is stored in the flash memory 22. The generaloperation control (i.e., control except for the download control)performed by the unit controller 20 is made on the basis of the programstored in the flash memory 22. The RAM 23 is used as a temporary storageunit used when the flash memory 22 is updated. The screen displaygenerator 24 generates various display signals under the control of theunit controller 20. This display signal is supplied to the adder 25 tobe superposed on the decoded video signal.

[0051] In this invention, a program for controlling the above receiver 6is transmitted through the communication satellite 5. More specifically,program data is supplied as additional data to the multiplexer 2,subjected to the above processes, transmitted from the transmissionequipment 4 together with video and voice which are high-efficientlyencoded by the MPEG2, and repeated by the communication satellite 5. Auser causes the receiver 6 to receive the transmitted program data, sothat, for example, an updating operation for the program of the receiver6 can be performed.

[0052] When a program is downloaded on the receiver 6, programinformation separated by the separation unit 11 is written in the RAM 23by the unit controller 20. A write operation is performed every unit ofupdating (e.g., 64 kbytes). Until the process corresponding to one unitof updating of the flash memory 22 is completed, the information is heldby the RAM 23. A program of one unit of updating is read from the RAM23, written in the flash memory 22, and then subjected to an updatingprocess. Until updating of all the programs to be downloaded iscompleted, the process of one unit of updating is repeated.

[0053]FIG. 4 shows an example of the arrangement of a data stream fortransmitting program data. In this example, program data is processedaccording to the form of a private section ruled by Systems (ISO13818-1). In the MPEG2, a data stream is handled in a component unitcalled a pack obtained by bundling a plurality of packets. In the pack,tow types of components, i.e., a section and a PES (Packtized ElementaryStream) packet are arranged depending on the types of streams to betransmitted or a data configuration. Control information or the like istransmitted by the section, and an image or voice is transmitted by thePES packet.

[0054] Also in a section, portions other than a header are determined onthe basis of the rules of the MPEG2. For example, a PAT (ProgramAssociation Table), a PMT (Program Map Table), and a CAT (ConditionalAccess Table) in which, e.g., the specification information of a programis transmitted, and the private section in which only a header isdetermined are arranged. A plurality of sections, e.g., 1,024 sectionsare gathered to constitute one table. In this embodiment, program datais stored in the private section to be transmitted.

[0055] As private sections, there are a short private section having aheader size of 3 bytes and a long private section having a header sizeof 8 bytes. Program data is stored in the short private section. Aheader is constituted by the first five regions, i.e., a table ID, asection syntax indicator, a private indicator, a reserved region, and asection length. In the remaining portion, program data and othernecessary data are stored.

[0056] The section in which the program data is stored is called a loadsection. The table ID having 8 bits determines the contents of thesection. In this case, a value representing that the section is a loadsection is stored in the table ID. The section syntax indicatorindicates, as one bit, whether the header type of the section is a shorttype or a long type. For example, if the value of the section syntaxindicator is ‘1’, the long type is determined; if the value is ‘0’, theshort type is determined. The private indicator indicates whether thesection is a private section. If the value is ‘1’, it is determined thatthe section is a private section. In the 2-bit reserved region, ‘11’ isstored.

[0057] In the section length, the number of bytes of the section startedimmediately after 12 bits determined as the section length is stored. Upto the section length, the header is ended. Since 12 bits are allocatedto the section length, a maximum of 4,096 bytes can be expressed. Morespecifically, data having a maximum of 4,096 bytes can be stored in theregions following the region of the section length.

[0058] A maker ID has 8 bits, and represents a receiver makeridentification number for identifying the maker of a receiver. Morespecifically, different receiver maker identification numbers areallocated to the makers of receivers in advance. A model ID having 8bits represents a model identification number for identifying the modelof a receiver. The model identification number can be uniquely allocatedto each maker. More specifically, different makers (receiver makeridentification numbers) may have the same model identification number.When the maker ID and the model ID are combined to each other, areceiver can be specified.

[0059] A version ID has 8 bits, and represents the version of programdata transmitted by the private section. More specifically, the versionidentification number of program data corresponding to a model specifiedby the maker ID and the model ID is represented by the version ID.

[0060] The subsequent extended section number has 16 bits, andrepresents a section number Sno allocated to the section. The subsequentextended final section number has 16 bits, and represents the totalnumber Ssum of sections having the same table ID, the same maker ID, thesame model ID, and the same version ID.

[0061] The subsequent 8 bits are defined as a code data region, and themain body of program data is stored in this region. A plurality of codedata regions described above, e.g., N code data regions, can becontinuously set in the same section. Therefore, program data of (8×N)bits can be transmitted per section.

[0062] As described above, the maximum size of data which can be storedin the region following the header is limited to 4,096 bytes as asection length. For this reason, when the size of other data issubtracted from the size of 4,096 bytes, N is set to be 4,085 at themaximum. Since the total size of the program data is actually, e.g.about 2 MBytes, transmission of the program data is shared by aplurality of load sections. Different section numbers Sno are added tothe divided load sections, respectively. In this case, it is convenientfor the following processes that the section numbers Sno aresequentially added from the start of the program data.

[0063] The final CRC having 32 bits is CRC (Cyclic Redundancy Check)which is performed by data immediately before the CRC in this section.By using information in this CRC region, error detection of the sectionis performed.

[0064] As described above, a plurality of transponders are mounted onthe communication satellite 5, and transmission can be simultaneouslyperformed from the plurality of transponders in different frequencybands. In this case, the same program data are not transmitted from theplurality of transponders, respectively, but program data correspondingto receivers whose makers and models are different depending on thetransponders may be transmitted from the transponders. For example,program data corresponding to model b of maker a is transmitted fromtransponder A, program data corresponding to model d of maker c andmodel f of maker e are transmitted from transponder B, and program datacorresponding to model g of maker a and model i of maker h aretransmitted from transponder C. In this manner, program datacorresponding to different makers and different models are transmittedfrom the respective transponders.

[0065] Therefore, a transponder from which necessary program data istransmitted must be determined. FIG. 5 shows the arrangement of a datastream for transmitting information representing a specific transponderfrom which program data corresponding to a specific maker and a specificmodel is transmitted. Here, as in the above transmission of the aboveprogram data, a private section is used. However, in this example, aprivate section of a long header type is used.

[0066] This section is called a load control section. As the loadcontrol section, a load control section having the same contents istransmitted from each transponder. The first 3 bytes of the headerrepresent the same contents as that of the above load section. As amatter of course, a value representing a load control section is used asa table ID, and a section syntax indicator is set to be ‘1’ to representthat the header type is long.

[0067] A subsequent reserved region having 18 bits is filled with ‘1’. Aversion number, a current next indicator, a section number, and a finalsection number which follow the reserved region are set to be valuesdetermined by the MPEG2, respectively. Up to the final section number,the header is ended.

[0068] A transport stream ID having 16 bits represents the number Tno ofa transponder mounted on the communication satellite 5. Regionsextending from the transport stream ID to the position immediatelybefore CRC are repeated by the number of transponders (in this example,L transponders). More specifically, pieces of information shown in theregions extending from the transport stream ID to the positionimmediately before the CRC correspond to data transmitted by using onetransponder represented by the transport stream ID.

[0069] The subsequent 3-bit reserved region is filled with ‘1’. Thesubsequent download PID having 13 bits a PID used when a load section istransmitted from a transponder represented by a transponder number Tno.The subsequent 4-bit reserved region is filled with ‘1’.

[0070] A model information length having 12 bytes represents the numberof bytes of regions extending from the position immediately after themodel information length to the position immediately before the CRCregion of the end. The subsequent maker ID and model ID have 8 bitseach, and represent a receiver maker identification number and a modelidentification number, respectively. The receiver maker identificationnumber and the model identification number represent the correspondencebetween program data transmitted from a transponder represented by atransponder number Tno and a specific model being available from aspecific maker. The maker ID and the model ID are repeated depending onthe type of program data to be transmitted by using one transponder. Inthis example, M types of data are transmitted by using one transponder,and the maker ID and the model ID are repeated M times.

[0071] The final CRC having 32 bits is CRC (Cyclic Redundancy Check)which is performed by data stored up to immediately before the CRC inthis section. By using information in this CRC region, error detectionof the section is performed.

[0072] With the data stream constituted as described above, a user canautomatically download proper program data by only instructing thereceiver 6 to download the program data. More specifically, when loadcontrol sections in which the same contents are transmitted from therespective transponders are received, a transponder number Tno of atransponder from which proper program data is transmitted can be known.On the basis of the transponder number Tno, the proper transponder isautomatically designated in the receiver 6. Thereafter, a load sectiontransmitted from the corresponding transponder is received to check, onthe basis of the maker ID, the model ID, the version ID, and the like,whether the load section is proper. If the load section is proper,downloading is executed.

[0073] The download process will be described below in detail by usingthe flow charts shown in FIGS. 6 and 8. FIG. 6 shows processes performedwhen a transponder from which a load section corresponding to thereceiver 6 is transmitted is designated. In the first step S1, anarbitrary transponder is designated to receive a radio wave. Thereceived radio wave is subjected to predetermined signal processing bythe tuner 8 and the demodulator 9 as described above and errorcorrection by the error correcting unit 10. The stream of additionaldata is extracted by the separation unit 11. The stream of additionaldata is stored in a predetermined region of the RAM 23 through, e.g.,the unit controller 20.

[0074] The processes following the process in the next step S2 areexecuted under the control of the unit controller 20. In step S2, datastored in the CRC region is extracted from the stream of additional datastored in the RAM 23. An arithmetic operation performed by the CRC isperformed to check whether the transmitted data has an error. If anerror is detected, the flow returns to step S1 to receive a radio waveagain. If no error is detected, the flow shifts to step S3. In step S3,a table ID is acquired from the received data.

[0075] On the basis of the acquired table ID, it is checked whether thereceived data is a load control section (step S4). If it is determinedthat the data is not a load control section, the flow returns to stepS1.

[0076] Although not shown, in step S4, a private indicator included inheader information as shown in FIG. 4 or 5 is also used as a conditionfor the determination.

[0077] If it is determined in step S4 that the received data is a loadcontrol section, the flow shifts to step S5. Subsequently, processes areexecuted on the basis of the format shown in FIG. 5. In step S5, asection length is acquired. In the next step S6, the transponder numberTno is set to be an initial value, e.g., Tno₁. Subsequently, a downloadPID at the transponder number Tno₁ is acquired in step S7, and a modelinformation length at the transponder number Tno₁ is acquired in thenext step S8.

[0078] In step S9, the maker ID and model ID of program data transmittedfrom the transponder indicated by the transponder number Tno₁ isacquired. The process in step S9 is repeated (repeated M times in thisexample) on the basis of the model information length obtained in stepS7 by the determination in step S10. If it is determined that theprocesses with respect to the transponder Tno₁ are ended, the flowshifts to step S11 to check whether processes for the transponders areended. If it is determined that the processes are not ended, thetransponder number Tno is set to be the next number, e.g., Tno2 (stepS12), and the flow returns to step S7.

[0079] If it is determined in step S11 that the processes for thetransponders are ended, the series of processes are ended. When theprocesses shown in the flow chart in FIG. 6 are performed, thecorrespondence between transponders and the receiver makeridentification numbers (maker IDs) and model identification numbers(model IDs) of program data transmitted from the correspondingtransponders can be obtained. FIG. 7 shows an example of thiscorrespondence. In the receiver 6, the tuner 8 is controlled by the unitcontroller 20 based on the correspondence to designate a predeterminedtransponder.

[0080] More specifically, the maker ID and model ID of the receiver 6 isread from the ROM 21 by the unit controller 20, and the correspondenceshown in FIG. 7 is referred to. Therefore, a transponder from whichprogram data corresponding to the read maker ID and the model ID istransmitted can be known.

[0081]FIG. 8 shows a flow chart used when a radio wave from thedesignated transponder is received to download a program. First, apredetermined transponder obtained by the above correspondence isdesignated in the first step S20 to receive a radio wave. The receivedradio wave is subjected to the above processes to extract a stream ofadditional data. The stream of additional data is stored in the RAM 23.

[0082] Processes following the process in the next step S21 areperformed under the control of the unit controller 20. In step S21, datastored in the CRC region is extracted from the stream of additional datastored in the RAM 23. An arithmetic operation performed by the CRC isperformed to check whether the transmitted data has an error. If anerror is detected, the flow returns to step S20 to receive a radio waveagain. If no error is detected, the flow shifts to step S22. In stepS22, a table ID is acquired from the received data.

[0083] On the basis of the acquired table ID, it is checked whether thereceived data is a load section (download data) (step S23). If it isdetermined that the data is not a load section, the flow returns to stepS20.

[0084] Although not shown, in step S23, a private indicator included inheader information as shown in FIG. 4 or 5 is also used as a conditionfor the determination.

[0085] If it is determined in step S23 that the received data is a loadsection, program data is transmitted from this section. For this reason,subsequently, a download process is executed on the basis of the formatshown in FIG. 4. In the next step S24, a section length is acquired. Inthe next step S25, a maker ID, a model ID, and a version ID areacquired. In step S26, it is checked whether the program data to betransmitted from the load section should be downloaded.

[0086] A maker ID and a model ID are read from the ROM 21 by the unitcontroller 20. It is checked whether the read maker ID and the readmodel ID coincide with the maker ID and the model ID acquired in stepS24. If these IDs do not coincide with each other, it is determined thatthe target program data is not transmitted from the load section.

[0087] If these IDs coincide with each other, the version ID of theprogram data stored at present is read from the flash memory 22. When aprogram data is to be stored in, e.g., the flash memory 22, this versionID is set as the attribute of the program data. This version ID and theversion ID acquired in step S25 are compared with each other. If it isdetermined as the comparison result that the version ID acquired in stepS25 is newer than the version ID of the program data, it is determinedthat target program data is transmitted from the load section, and theflow shifts to step S27.

[0088] Because of the comparison between version IDs, program data of aversion which is the same as that of the program data stored in theflash memory 22 at present or program data of an old version can beavoided from being downloaded in vain.

[0089] In step S27, a section number Sno and a total section number Ssumare acquired. The section number Sno and the total section number Ssumare stored in, e.g., the RAM 23, and held until all the program data arecompletely downloaded. In the next step S28, it is checked whether aload section which is received at present is a section which does nothave been acquired. This determination is made on the basis of thesection number Sno.

[0090] For example, each time a load section is received, the sectionnumber Sno acquired in step S27 is accumulatively stored in the RAM 23,and a table of the section numbers Sno of load sections which have beenacquired is formed. Each time a new section number Sno is acquired, thetable is referred to to check whether a download process is performed(to be described later).

[0091] If it is determined in step S28 that the section is not a sectionwhich does not have been acquired, the flow returns to step S20 toreceive the next load section. On the other hand, if it is determinedthat the section is a section which is not acquired, the flow shifts tostep S29 to acquire program data from the code data region, and the mainbody of the program is downloaded. The downloaded program data istemporarily stored in a predetermined region of, e.g., the RAM 23.

[0092] The program data, as shown in FIG. 4, is stored in code dataregions divided into N regions each having a size of 8 bits. The size ofthe program data stored in the load section can be recognized dependingon the section length obtained in step S24 described above, and thevalue of N can be known. On the basis of the value of N, it is checkedin step S30 whether the program data is downloaded by a predeterminedsize. If the download process for the predetermined size is not ended,the flow returns to step S29 to cause the download process to continue.

[0093] If it is determined in step S30 that the download process for thepredetermined size is ended, the flow shifts to step S31. In step S31,it is checked whether a download process for a series of load sectionsin which the program data is stored is ended. This determination is madewith reference to, e.g., the section number Sno accumulatively stored inthe RAM 23. If it is determined that the download process is not ended,the flow returns to step S20 to perform a download process for theremaining sections.

[0094] If it is determined in step S31 that the download process for aseries of load sections is ended, it is determined that the downloadprocess for the entire program data is completed. The series ofprocesses are ended.

[0095] The download process for the entire program data is completed,the program data stored in the RAM 23 is transferred to the flash memory22 by a predetermined method to be written in the flash memory 22. Thisprocess is performed on the basis of, e.g., a loader program stored inthe ROM 21 in advance.

[0096] The progress state of downloading may be preferably displayed inthe above download process. This progress state can be easily calculatedby, e.g., execution of the process in step S29 in FIG. 8 on the basis ofthe total section number Ssum, the section number Sno accumulativelystored, the section length acquired in step S4, and the number ofrepeats of steps S29 and S30. Therefore, a percentage of downloadedprogram data to the entire program data at present can be displayed asin an example shown in FIG. 9. This display is performed by thefollowing manner. That is, a display screen is formed by the imagedisplay generator 24 on the basis of the control of the unit controller20, and the display screen is synthesized with an output from a videosignal unit 12 by the adder 25.

[0097] Program data is downloaded in the above description. However, thepresent invention is not limited to this example. For example, data tobe transmitted can be easily transmitted as text data, still image data,or moving image data as if messages such as information of new productsor update information of programs are transmitted from the maker of areceiver.

[0098] As has been described above, according to the present invention,different program data can be transmitted for receiver makers andmodels, respectively. For this reason, even if a host processor, an OS,an interpreter, and the like are not integrated on the reception side,program data for all receivers can be advantageously downloaded.

[0099] According to the present invention, since the version informationof program data to be transmitted can be known by a version ID, adownload process can be advantageously avoided from being performed invain.

[0100] Further, according to the embodiment, the progress state ofdownloading can be advantageously displayed. For this reason, even ifdownloading is performed for a relatively long period of time, stresscan be advantageously avoided from acting on a user.

[0101] Furthermore, according to the present invention, when there aremany makers or models, program data corresponding to the makers or themodels can be advantageously transmitted by arbitrary transponders.

What is claimed is:
 1. A data transmission device for time-divisionallymultiplexing signals of a plurality of channels and further multiplexingthe plurality of time-divisionally multiplexed signals to simultaneouslytransmit the signals, characterized in that receiver makeridentification information for identifying makers of reception devicesfor receiving transmitted information and receiver model identificationinformation for identifying models of the makers of the receptiondevices are transmitted.
 2. A data transmission device according toclaim 1 , characterized in that version identification information ofthe information is further transmitted.
 3. A data transmission deviceaccording to claim 1 , characterized in that quantity informationrepresenting the quantity of the information is further transmitted. 4.A data transmission device according to claim 1 , characterized in thatinformation representing specific signals, of the multiplexed andtransmitted signals, through which the receiver maker identificationinformation and the receiver model identification information aretransmitted is further transmitted to each of the multiplexed andtransmitted signals.
 5. A data reception device for designating apredetermined signal from multiplexed and transmitted signals to receivethe predetermined signal, characterized by comprising: means forextracting only necessary information on the basis of receiver makeridentification information and receiver model identification informationincluded in the received signal to store the extracted information; andcontrol means for using the stored information as a program for unitcontrol.
 6. A data reception device according to claim 5 , characterizedin that a progress state of the storing is displayed on the basis ofquantity information representing the quantity of the informationincluded in the received signal.
 7. A data transmission system fortime-divisionally multiplexing signals of a plurality of channels andfurther multiplexing the plurality of time-divisionally multiplexedsignals to simultaneously transmit the signals, and designating apredetermined signal from the multiplexed and transmitted signals toreceive the predetermined signal, characterized by comprising:transmission means for transmitting receiver maker identificationinformation for identifying makers of reception devices for receivingtransmitted information and receiver model identification informationfor identifying models of the makers of the reception devices; receptionmeans for receiving the transmitted information; means for extractingonly necessary information on the basis of the receiver makeridentification information and the receiver model identificationinformation included in the received information to store the extractedinformation; and control means for using the stored information as aprogram for unit control.
 8. A data transmission method fortime-divisionally multiplexing signals of a plurality of channels andfurther multiplexing the plurality of time-divisionally multiplexedsignals to simultaneously transmit the signals, characterized in thatreceiver maker identification information for identifying makers ofreception devices for receiving transmitted information and receivermodel identification information for identifying models of the makers ofthe reception devices are transmitted.